This proposal has two inter-related specific aims which will be accomplished as part of a single large study: (1) to evaluate thermal biofeedback (TBF) in a controlled trial as a non-drug treatment for mild essential hypertension; (2) to compare two different maintenance conditions in a 12-month follow-up of the initial treatment successes. Study 1 will provide a more definitive test of the efficacy of TBF in the treatment of mild hypertension than has previously been available while Study 2 will provide preliminary data on how to improve maintenance of initial BP reductions. Forty unmedicated patients with mild hypertension will be randomly assigned to 16 sessions of TBF conducted in smll groups, over 8 weeks of TBF, or an 8-week program of BP monitoring (as a control condition) to meet Aim 1. Initial outcome, successful reduction of BP, will be evaluated both by office BPs with random zero sphygmomanometers and by 24-hour ambulatory BP monitoring. Successfully treated patients (estimated to be 70-80%) will be randomly assigned to one of two maintenance conditions and followed for up to 12 months: (a) a standard follow-up with once-per-3-month laboratory visits and instructions to continue home-practice of the TBF and regular monitoring of home BPs; (b) an enhanced maintenance condition with once-per-month booster treatments, use of electronic home TBF devices, and increased expectations of success.